how to mark and identify mice/rats

I have 50 mice for genotyping. But I don't know how to mark mice for my expirement.
What I am using is make lines on the tail with a marker, but it only lasts for 3 days.
Anyone can tell me the standard method, punch ears, cut nails?
thanks!

I have 50 mice for genotyping. But I don't know how to mark mice for my expirement. What I am using is make lines on the tail with a marker, but it only lasts for 3 days.Anyone can tell me the standard method, punch ears, cut nails? thanks!

some people punch ears... others mark them with permenant dye colors!!!some others shave on different regions... (Tricky.. need to keep track)

I use ear punching. You're going to need to be trained by someone, do you have a professor or TA who could show you? If not, one of your facility's Animal Care Technicians may be able to help you if you ask.

In my experience, It's easier to number a few mice in each cage, rather than try to accurately punch every number 1-99. What I'd do is: say you have a cage with 5 mice, mark them NM (no mark, no punch), R (1 hole in right ear), L (1 hole in left ear), RR (2 in right ear), LL (2 in left ear). So your cage would look like this:

NMRLRRLL

... a cage with 2 mice in it would just be NM, R, make sense? Hope this was helpful I love working with my mice.

Personally I'm not a fan of the ear tags, as they can tear out. At best you get a little mouse with a big, awkward looking tag flopping around.

We recently tried the mouse tattoo kit in my lab with great success. So far we've only tried doing mouse toes.... waiting to get committee approval for mouse ears
But I think inking ears will be a further improvement over toes, since you won't have to pick up each animal and examine its feet.

i've tried by staining with picric acid. its supposed to be in powder form. But the one I have is in solution. What I did was I dip cotton bud into the picric acid, and stain the mice according to my number coding (right front hand = 1, left front hand = 2, right flank = 3, left flank = 4, head =5). I tried this last 2 weeks, and the dye still there and all the mice are ok (no sign of abnormality). just make sure they don't lick the dye before the dye dried. you can apply it by holding the mice by tail.